Integrated quality assurance for in image guided radiation treatment delivery system

Abstract

A method and apparatus for quality assurance of an image guided radiation treatment delivery system. A quality assurance (“QA”) marker is positioned at a preset position under guidance of an imaging guidance system of a radiation treatment delivery system. A radiation beam is emitted from a radiation source of the radiation treatment delivery system at the QA marker. An exposure image of the QA marker due to the radiation beam is generated. The exposure image is then analyzed to determine whether the radiation treatment delivery system is aligned.

1. A method, comprising:
 positioning a quality assurance (“QA”) marker at a preset position under guidance of an imaging guidance system of a radiation treatment delivery system; 
 emitting a radiation beam from a radiation source of the radiation treatment delivery system at the QA marker, the radiation source for delivering radiation according to prescribed treatment plans; 
 generating an exposure image of the QA marker due to the radiation beams, wherein the exposure image includes a beam exposure field, a center shadow cast by a central target of the QA marker, and a ring shadow cast about the center shadow by a ring target of the QA marker; and 
 analyzing the exposure image to determine whether the radiation treatment delivery system is calibrated. 
 
     
     
       2. The method of  claim 1 , wherein the QA marker comprises:
 a housing being translucent to the radiation beam for housing the central target and the ring target. 
 
     
     
       3. The method of  claim 2 , wherein the QA marker includes two ring targets disposed in the housing, each of the two ring targets positioned to have a ring axis aligned with a trajectory passing through a center of the central target. 
     
     
       4. The method of  claim 2 , wherein the QA marker further comprises fiducials for tracking the QA marker, and wherein positioning the QA marker at the preset position under guidance of the imaging guidance system includes:
 tracking the fiducials of the QA marker with the imaging guidance system; and 
 providing feedback to a positioning system of the radiation treatment delivery system to position the QA marker to the preset position based on the tracking. 
 
     
     
       5. The method of  claim 4 , wherein positioning the QA marker at the preset position under guidance of the imaging guidance system further includes:
 generating a reference image of the QA marker illustrating the fiducials using a first imaging modality; and 
 registering the fiducials of the reference image with a real-time image of the fiducials generated by the imaging guidance system. 
 
     
     
       6. The method of  claim 2 , wherein analyzing the exposure image to determine whether the radiation treatment delivery system is calibrated comprises analyzing relative positions of one or more shadows and a beam exposure field in the exposure image. 
     
     
       7. The method of  claim 6 , wherein analyzing the exposure image to determine whether the radiation treatment delivery system is calibrated further comprises:
 analyzing the exposure image to determine centroids of a center shadow, a ring shadow, and a beam exposure field in the exposure image; and 
 determining whether the centroids of the center shadow, the ring shadow, and the beam exposure field are concentrically aligned. 
 
     
     
       8. The method of  claim 2 , wherein analyzing the exposure image to determine whether the radiation treatment delivery system is calibrated comprises analyzing the exposure image to determine whether the radiation source, the imaging guidance system, and a treatment couch supporting the QA marker are aligned with each other. 
     
     
       9. The method of  claim 1 , wherein emitting the radiation beam from the radiation source comprises emitting a first radiation beam from the radiation source located at a first position and further comprising:
 translating the radiation source to a second position; and 
 emitting a second radiation beam from the radiation source at the second position. 
 
     
     
       10. The method of  claim 9 , wherein generating the exposure image of the QA marker comprises generating a first exposure image of the QA marker due to the first radiation beam and further comprising:
 generating a second exposure image due to the second radiation beam; and 
 analyzing the second exposure image to determine whether the radiation treatment delivery system is aligned. 
 
     
     
       11. The method of  claim 10 , wherein the first and second radiation beams have substantially orthogonal trajectories. 
     
     
       12. A radiation treatment delivery system, comprising:
 a positioning system to position an alignment target to a preset position; 
 a detector; 
 a therapeutic radiation source adjustably positioned to emit a radiation beam passing through the preset position and impingent upon the detector and, 
 a quality assurance (“QA”) marker positioned at the preset position, the QA marker including the alignment target to cast a first shadow on the detector within a beam exposure field of the radiation beam, a relative position of the first shadow and the beam exposure field for verifying alignment of the positioning system and the therapeutic radiation source; 
 wherein the alignment target of the QA marker includes:
 a spherical target disposed within a housing of the QA marker to cast the first shadow on the detector in response to the radiation beam; and 
 a first ring target disposed within the housing to cast a ring shadow on the detector in response to the radiation beam, wherein a ring axis of the first ring target is substantially aligned with a trajectory passing through a center of the spherical target, wherein the first ring target has a larger inner diameter than a diameter of the spherical target. 
 
 
     
     
       13. The radiation treatment delivery system of  claim 12 , further comprising an imaging source mounted to emit imaging signals at the preset position, the detector positioned to image the QA marker in response to the imaging signals, the positioning system to adjust a position of the QA marker in response to real-time feedback from the detector. 
     
     
       14. The radiation treatment delivery system of  claim 12 , wherein the alignment target further includes a second ring target disposed within the housing to cast a second ring shadow on the detector in response to a second radiation beam from the therapeutic radiation source, wherein a second ring axis of the second ring target is substantially aligned with a trajectory passing through a center of the spherical target. 
     
     
       15. The radiation treatment delivery system of  claim 14 , wherein the first and second ring axes are substantially perpendicular to each other and wherein the alignment target provides rotational and translational alignment validation therapeutic radiation source. 
     
     
       16. A machine-readable storage medium that provides instructions that, when executed by a therapeutic patient treatment system, will cause the therapeutic patient treatment system to perform operations comprising:
 positioning a quality assurance (“QA”) marker at a preset position under guidance of an imaging guidance system; 
 emitting a radiation beam from a radiation source at the QA marker; 
 capturing an exposure image of the QA marker due to the radiation beam wherein the exposure image includes a beam exposure field, a center shadow cast by a spherical target of the QA marker, and a ring shadow cast about the center shadow by a ring target of the QA marker; and 
 analyzing the exposure image to determine whether a radiation treatment delivery system is aligned. 
 
     
     
       17. The machine-readable storage medium of  claim 16 , wherein analyzing the exposure image to determine whether the radiation treatment delivery system is aligned comprises analyzing a relative position of the beam exposure fields, the center shadow, and the ring shadow. 
     
     
       18. The machine-readable storage medium of  claim 17 , wherein analyzing the exposure image to determine whether the radiation treatment delivery system is aligned further comprises:
 analyzing the exposure image to determine centroids of the center shadow, the ring shadow, and the beam exposure field; and 
 determining whether the centroids of the center shadow, the ring shadow, and the beam exposure field are concentrically aligned.